While it would have been nice to tackle this issue before the election, Google and Facebook are finally taking a tiny step in order to fight back against fake news. According to multiple statements, both companies have updated their policies to ban fake news sites from using Facebook’s and Google’s advertising networks.

With the U.S. election, fake news became incredibly popular on social networks, such as Facebook, Twitter and YouTube, as well as news aggregating services, such as Google News and news articles in Google search results. We’re not talking about opinion articles — we’re talking about reports spreading blatantly inaccurate information.

This Facebook trending story is 100% made up.Nothing in it is true.This post of it alone has 10k shares in the last six hours. pic.twitter.com/UpgNtMo3xZ

Google first updated its policy saying that the company will try to ban sites that “misrepresent, misstate, or conceal information.” Websites who don’t comply with this rule will get banned from using Google AdSense.

When it comes to Facebook, the company has also updated its policy to rule out fake news sites from using Facebook Audience Network.

Google AdSense and Facebook Audience Network let content publishers display ads on their websites. Google and Facebook manage the ad inventories, content publishers get a cut for clicks or impressions.

Both companies already have strict policies for their ad networks. For instance, you can’t use Google AdSense on a porn website. Google uses a combination of algorithms and human moderation to decide whether a site is eligible to use its advertising service.

By removing a potential revenue stream, it makes the business of fake news a bit less lucrative. For instance, Buzzfeed discovered that more than 100 fake news sites were created in a tiny city in Macedonia. So it’s clear that it’s not just about influencing the election — people are taking advantage of social networks to make money using fake news.

But there will always be alternative revenue streams, so this move is not enough. Reducing the reach of these websites is the best way to prevent fake news sites from popping out. If Facebook, Twitter, Google News and other websites flagged fake news appropriately, then there would be no reason to create fake news sites in the first place.